I once watched Neil Armstrong sign his name, and it appeared to be one of the hardest things he’d ever done. Not because he was infirm — though in 2010 he was clearly looking frail — and not because his signature wasn’t still the strong and spiky cursive that was always as much calligraphy as it was mere handwriting. It was because for more than 41 years, writing his name was all people seemed to want him to do. For a uniquely private man, the offering up of the autograph had become an act of surrender, of obeisance, even of commerce — as the signature he handed over in a restaurant on a Monday would wind up for sale at an autograph show on a Tuesday. So he just stopped doing it — until one day he had to.

That day was in March 2010, when he, Gene Cernan and Jim Lovell — moon men all — were part of a morale tour of American military bases in the Middle East. I went along on the tour as well, and on this particular evening, our group — well, the three astronauts, actually — were being feted at an outdoor party at the residence of the commander of the local U.S. naval fleet. When we arrived, we could see that there was a queue to enter the residence — a queue that was moving unusually slowly because there was a guest book at the door that attendees were expected to sign. Armstrong, the man of principle and hounded legend, could not sign; Armstrong, the ex-Navy man, could not not. So Armstrong the pragmatist split the difference. When his turn came, he took the pen, stood for a moment — and then scribbled something wholly illegible. There was a capital N, to be sure, but what followed was just a brief dash of gibberish. He then put down the pen and entered the party — and I still half-suspect the page wound up on eBay the next day.

Armstrong was a man of almost preternatural imperturbability. That, of course, is true of all of astronauts — especially those from the early era. He, like so many others, was a military pilot. In his case, the piloting included 78 combat missions over Korea, during one of which his plane was crippled by antiaircraft fire. He managed to stay airborne long enough to limp back into American-held territory before he bailed out. He retired from the Navy after the war and became a test pilot for the National Advisory Committee for Aeronautics (NASA’s predecessor) and flew 900 different types of aircraft — all of them fit only for test pilots because no one could say with any certainty whether the things would perform as designed or would simply shake themselves to rivets once they reached flight speed.

It wasn’t until 1962 that Armstrong joined NASA — in the second crop of astronauts chosen after the glorious Original Seven. On at least three occasions that followed, the machines he flew tried to kill him.

On March 16, 1966, Armstrong and his crewmate David Scott rode Gemini 8 to orbit, commencing what was supposed to be a five-day mission, but that lasted little more than 10 hours. Less than five hours into the flight, they chased down and docked with an Agena Target Vehicle — an unmanned craft significantly larger than their own Gemini capsule, designed to help astronauts practice the maneuvers they’d need to execute during later lunar missions. Not long after they docked, the paired ships began spinning out of control, barrel-rolling to the right.

NASA’s protocols — which were not necessarily Armstrong’s protocols — were that if anything went wrong they should undock from the Agena immediately, since surely the problem would be in the less exquisitely engineered of the two ships. So Armstrong did what the rules dictated — and the roll rate only increased. The malfunction, it turned out, was in the Gemini spacecraft — a stuck thruster that wouldn’t stop firing. Releasing the deadweight of the Agena only accelerated the spin.

“The rate was about one revolution per second,” Scott says. “We were approaching vertigo — with tunnel vision, loss of consciousness and all the rest.” Armstrong shut down the main thrusters, fired up the backup system and brought his bucking spacecraft to heel. That was at about 8 p.m., Houston time. By 10:22 p.m., he and Scott were safely bobbing in the Pacific.

Two years later, Armstrong was flying a far more ignoble machine — the ugly, insectile Lunar Landing Training Vehicle (LLTV). The 22-ft. (6.7 m), 2,500-lb. (1,100 kg), four-legged contraption was never supposed to climb much more than 1,000 ft. (300 m) off the ground and was intended, as its name makes clear, to allow Apollo pilots to practice landing the lunar module — a spacecraft they would never get to fly for real until the day they were required to try to set it down on the surface of the moon. On May 6, 1968, Armstrong had the thing just a few hundred feet off the ground at Ellington Air Force Base in Texas, when it stopped responding to his commands, violently swinging first one way, then the other. When the LLTV went into a straight, shallow dive, it was clear the game was over. Armstrong ejected, the LLTV crashed, and he descended gently to the ground, passing directly through the oily cloud of black smoke the wrecked machine was giving off.

An hour later, astronaut Al Bean heard the news, and dashed over to Armstrong’s Ellington office hoping, but not really suspecting, he’d be there. Bean found the future first man on the moon sitting at his desk, filing paperwork. He spluttered something about the accident and asked if Armstrong was O.K. “Mm-hmm,” came the response. History did not record if Armstrong ever looked up.

It was the lunar module Eagle that nearly took out Armstrong the final time, when he and Buzz Aldrin were making their final approach to their Tranquility Base landing site on July 20, 1969. Tranquility Base had been extensively mapped by unmanned orbiters and while NASA knew the eyesight of the orbiters was not sharp enough to resolve objects as small as boulders, they reckoned they could recognize a boulder field when they saw one from the surrounding topography. So the Lunar Excursion Module’s (LEM) computer was supposed to handle the actual landing — which it did just fine until Armstrong and Aldrin were making their final approach, when the warning-panel flashed what was called a 1202 alarm and then a 1201, both indicating that the system was overloaded and could process no more. The LEM, by then, was exceedingly low on fuel — and if the needle hit empty there’d be no running on the residue sloshing in the tank that motorists call fumes and astronauts call blowdown. Empty meant empty, and that meant shutdown.

And then, of course, the boulders appeared. All over the prime landing zone were massive rocks impossible to navigate and deadly to try even to approach. Armstrong took the stick from the harried computer, tilted the half-upright LEM into a head-forward lean and flew in the flat across the boulder field, finally touching down on a spot of soil that had been wholly unremarkable for the entire 4 billion years of the moon’s existence and would now become the most powerfully evocative patch of real estate in all of human history. There were, NASA later calculated, about 30 seconds of fuel left in the tank.

There was a sweet smallness to what was then — and perhaps still is — humanity’s grandest and most improbable achievement. The moon, after all, is only 239,000 miles (385,000 km) from Earth — or far less than a lot of frequent travelers log on passenger planes each year. Armstrong’s and Aldrin’s entire time outside the LEM was 2 hr. 31 min. — and in all that time they never wandered very far from the safety of their little ship. If the landing sight were a baseball field and the LEM landed on the pitcher’s mound, the astronauts never got out of the infield — except for a brief detour Armstrong made to North Crater in shallow right field. They were back on Earth just four days later.

But never mind that. Armstrong, Aldrin and Michael Collins came home heroes — Armstrong the greatest among them. He accepted a teaching post at the University of Cincinnati, delivered speeches when he absolutely had to and served, when called — most notably on the investigation panels after the near disaster of Apollo 13 and the true disaster of the shuttle Challenger. He was only 38 when he walked on the moon, but he surely knew that if he lived to be 100 — or 82 as we now know it worked out — his life would forever be framed and defined by the 151 minutes he spent on the moon.

Armstrong seemed to make peace with that early on — even if he was never entirely comfortable with it. One evening during that Middle East tour, all the astronauts were onstage before an audience of service members young enough to be their grandchildren. During the question-and-answer session, one soldier asked Armstrong if he wouldn’t mind taking the mike and, well, saying the words — the words, those one–small–step words. I winced, and I suspect Lovell and Cernan did too. This was dog-and-pony stuff of the highest order. Armstrong just smiled and reached for the mike. His hand seemed shaky and his voice was weak — not the clear Midwestern tones that were spoken in 1969 and have been heard and heard and heard ever since. But he spoke the words all the same — and the audience roared and the applause rained down, and it was just the coolest and grandest and finest thing you could ever hope to see.